Source : Webster's Revised Unabridged Dictionary (1913)

Calumnious \Ca*lum"ni*ous\, a. [L. calumniosus.]
   Containing or implying calumny; false, malicious, and
   injurious to reputation; slanderous; as, calumnious reports.

         Virtue itself 'scapes not calumnious strokes. --Shak.

   Syn: . Slanderous; defamatory; scurrilous; opprobrious;
        derogatory; libelous; abusive. -- {Ca*lum"ni*ous*ly},
        adv. -- {Ca*lum"ni*ous*ness}, n.

Source : WordNet®

calumnious
     adj : (used of statements) harmful and often untrue; tending to
           discredit or malign [syn: {calumniatory}, {defamatory},
            {denigrative}, {denigrating}, {denigratory}, {libellous},
            {libelous}, {slanderous}]